Territory



(No Model.)

J. ODONNELL. VALVE GEAR FOR STE-AM ENGINES.

Patented Feb. 7,1882.

INV'ENTOR 09W WITNESSES ATTORNEYS;

N. PETERS. Phumumo n hu, Washington D. c.

UNITED STATES PATENT Orrrcs.

JAMES ODONNELL, OF CENTRAL CITY DAKOTA TERRITORY.

VALVE-GEAR FOR STEAM-ENGINES.

' SPECIFICATION forming part of Letters Patent No. 253,417, datedFebruary '7, 1882.

Application filed October 12, 1881. (No model.) I i To all whom it mayconcern:

Bejit known that I, JAMES ODONNELL, of Central City, in the county ofLawrence, Dakota Territory, have invented a new and useful Improvementin Valve-Gear for Steam- Engines; and I do hereby declare that thefollowing is a full, clear, and exact description of the same.

I employ two piston-valves which are rigidly connected, and hencereciprocate simultaneous- 1y to alternately open and close the portsleadingto the main cylinderof theengine. Contiguous to eachvalve-cylinder is a steam-chest containing puppet-valves, which areoperated to alternately admit steam into the small pistonchamber, fromwhich it passes into the main cylinder. 4

My invention is mainly embodied in the mechanism I employ to operatesaid puppet-valves, and I will now proceed to describe the same inconnection with otherparts forming a complete engine, by reference toaccompanying drawings, in which- Figure 1 is a side view of the engine,the valve-gear being shown in such position that both sets'ofpuppet-valves are closed. Fig. 2 is a plan View omitting thecrank-shaft. Fig. 3 is a vertical section'on line m m, Fig. 2. Fig. 4 isa rear view of the valve-gear, showing the position of the cams andratchets when the segmental gear is on the ha-lf-stroke. Fig. 5 is across-section of the same parts as in Fig. 4.. Fig. 6 is a frontsectional view, showing the valve gear and puppet-valves connectedtherewith, the pistons being on the half-stroke to the right. Fig. 7illustrates the construction and arrangement of the upper portion of thevalveear.

The letter A indicates the main cylinder of the engine, whose piston isconnected by a rod, B, with the crank-arm a of a driving-shaft, O, inthe usual way. Two small piston-cylinders, D D, are attached inhorizontal position to the side of the main cylinder A. Such cylinders Dare each provided with a reciprocating piston, E, the two being rigidlyconnected by a rod, F, which is attached to the shortarm b of shaftO.The small crank b is set quartering with the main crank a. Bothpistons Ereciprocate together to alternately open and close the ports 0 0,leading from cylinders D D into the said main cylinder. The pistons E Eare located the same distance apart as the ports 0 a, so that one of theformer will open one of said ports while the other is closed. whichoperation allows the requisite induction and exhaust of the maincylinder A. I

At the inner end of each small cylinder D is arrangeda steam-chest, G,which communicates therewith by a suitable port. Each steam-chest G hastwo apertured horizontal partitions, Fig. 3, in which two puppet-valves,H, are-seated, those of each pair being connected by a vertical stem, d.The function of these valves is to control admission of steam to thecylinders D D, and thereby also to the main cylinder A. The stems d ofthe respective sets of valves H are pivoted to the opposite ends ofayoke orbar, I, having downwardlycurved arms 6. This bar is oscillatedvertically by the revolution of cams K, Figs. 4 and 5, on which its endsrest, thereby alternately raising and lowering the two sets ofpuppet-valves H. The cams are keyed on the shafts L, and to imparttherequired intermittentrotary movement to the latter I employ thefollowing-described mechanism: Ratchet disks M are mounted first on saidshafts L, and pinionsN are loose thereon. Thelatter havespring-pawlsf,\vhich engage with teeth formed on opposite sides of theratchet-disks M. Such engagement takes place when the pinions arerotated in one direction, but when rotated in the other the pawls rideover the teeth, and hence do not rotate the ratchets. A large segmentalgear, O,

is journaled on a rigid support at a point equidistant between thepinions N and meshes with both. The lower portion of the gear 0 isconnected with the jointed end of rod P, which is attached to thesamecross-head asthe pistonsE.

The operation of the engine is as follows: As before stated, thepuppet-valves H control admission ofsteam to the small cylinders D D,from which it enters the main cylinder A through lateral ports 0. Thevalves H are ho wever raised, and the steam enters the cylinders D-D amoment before the pistons E move far enough to open the ports 0 c, andhence the steam, acting meanwhile on such pistons, aids materially inrotating the crank-shaft O, and thereby in driving the engine.

In Figs. 1 and 2 the crank 12 is in such position that the pistons E Eare at the limit of their movement to the right. gear 0 has thereforeswung from left to right, andin doingso has opened and closed therighthand puppet-valves H, the left-hand valves H meanwhile remainingclosed. This operation is due to the fact that when the pinions N rotatein onedirection the pawlsf pivoted thereto engage with the ratchets M,and thereby rotate the shafts L and cams K, thus causing the latter toraise one end of the bar I. One of the cams is raised to the verticalwhen the segmental gear 0 reaches the h alt-stroke, Figs. 3, 4, 5, 6;but as soon as the cam passes a little beyond the vertical the weight ofthe bar I carries it down into horizontal position. Thus at eachmovement of the pistons E E to the right the right-hand cam completes ahalf-revolution to the right, the right-hand puppetvalves B beingthereby opened and closed, and on the returnstroke (to the left) theleft-hand cam, Fig. 4., is rotated to theleft, thereby opening andclosing the left-hand puppet-valves H. Thus one or the other cam K isalways vertical, and one or the other set of puppet-valves H is alwaysopen when the segmental gear completes half its movement; but both camsThe segmental are horizontal and both sets of valves are closedat theend of the movement, so that steam enters the main cylinder and worksexpansively. In other words, steam enters the respectivepiston-cylinders D D on the half-stroke, and the valves H then close soas to cut off steam from the main cylinder directly after the pistons EE open the ports 0 c.

To prevent the noise and injury that would be occasioned if the valves Hshould seat too quickly, I employ curved plate-sprin gs R,which areattached to a fixed portion of the engineframe in vertical position, soas to press against the end of the cam when passing from the verticalposition to the horizontal.

What I claim is In combination with the main cylinder, cylinders D D,and the pistons E E for controlling admission of steam to the former,the puppetvalves for controlling induction and exhaust of said cylindersD D, the gearing, cams, camshafts,and piston-rod F, substantially asshown and described.

JAMES ODONNELL. Witnesses:

JAMES WATT, WILLIAM H. CHENEY.

